A professor, an economist and a judge sat in a room, crunched the numbers and reached this conclusion: More often than not, judges (in this case federal judges)  vote along party lines.

So say Lee Epstein, a professor at the University of Southern California, William M. Landes, an economist at the University of Chicago, and Richard A. Posner, a federal appeals court judge in Chicago, in their new book, The Behavior of Federal Judges, previewed in today’s New York Times by Adam Liptak. 

“Justices appointed by Republican presidents vote more conservatively on average than justices appointed by Democratic ones, with the difference being most pronounced in civil rights cases,” they write in the book.

A recent decision by the 6th U.S. Circuit Court of Appeals rejecting Michigan’s constitutional ban of affirmative action policies bears out that party allegiance, Liptak notes.  ”Every one of the eight judges in the majority was nominated by a Democratic president,” he said. “Every one of the seven judges in dissent was nominated by a Republican president.”

As Liptak adds:

Many judges hate it when news reports note this sort of thing, saying it undermines public trust in the courts by painting them as political actors rather than how they like to see themselves — as disinterested guardians of neutral legal principles.

But there is a lot of evidence that the party of the president who appointed a judge is a significant guide to how that judge will vote on politically charged issues like affirmative action.

True, federal judges are appointed, and perhaps that’s the news peg here, as they’ve long been perceived as above the fray of electoral posturing and politicking.

Is it any different in places where judges are elected?  Nobody’s run the numbers yet,  but one thing’s likely.  Judges who campaign are well-versed in the partisan give-and-take.